# Tycho Brahe: a picture of scientific life and work in the sixteenth century/Index

INDEX.

Aalborg, friend of T., 23.

Abul Hassan, inclination of lunar orbit, 343.

Abul Wefa, armillas, 316; meridian circle, 318; lunar variation, 339. Accuracy of T.'s observations, 356, 387.

Ahmed Ibn Abdallah, eclipse of year 829, 323.

Al Batraki, trepidation, 355.

Al Battani, time determinations, 323; fixed stars, 354; trepidation, 355.

Albumassar, distance of comets, 48.

Al Chogandi, sextant of, 326, 328.

Alhazen, refraction, 80, 334, 336.

Almegist, translations of, 3, 347.

Alphonsine tables, 3, 18, 19, 30, 52, 54, 133, 145, 155, 175 334, 355.

Al Sagani, quadrant of, 328.

Altitudes for time determinations, 323, 325.

Alzerkali, trepidation, 355.

Andreas, servant of T., 272; pupil of T., 275.

Annual equation, 306, 339, 340.

Apianus, Peter, book on astronomy, 6, 79; direction of comets' tails, 45, 166; latitude of Königsberg, 124.

Apianus, Philip, son of Peter, 34.

Apollonius of Perga, planetary system of, 274, 304.

Arbuthnot suggests to publish T.'s observations, 375.

Argelander, place of *Nova*, 67; accuracy of T.'s observations, 356.

Aristarchus, solar system, 167.

Aristillus used armillæ, 315.

Aristotle, ideas about comets, 63, 160.

Armillæ, 315.

D'Arrest, region about *Nova*, 67; ruins at Hveen, 379.

Assistants, 117, 280, 288, 302, 381, 382.

Astrolabium, 316, 318.

Astrology, practice of, 21, 24, 49, 54, 68; oration on, 74; calendar, 133; principles of, 146; T.'s opinion of, 155, 384.

Augsburg, T.'s visits to, 30, 81. *See* Quadrant.

Augustin on T.'s meridian line, 359.

Aurora observed at Hveen, 206.

Axelsen, Cort, assistant to T., 215, 384.

Azimuth, circles, 321; supposed error of, 358.

Bachazek, rector, Prague University, 303.

Bachmeister, professor at Rostock, 26, 308.

Barleben succeeds T. at Hveen, 376.

Barneweld, Dutch statesman, 270.

Bartholin, E., prepares to publish T.'s observations, 373, 374.

Barwitz, Austrian statesman, 269, 278, 369.

Basle, visits to, 29, 81; T. proposes to live at, 84.

Battus, professor at Rostock, 25.

Behaim, geographer, 5.

Below, friend of T., 155, 163, 384.

Benatky Castle, description, 281; new buildings, 286; T. leaves, 298.

Bessarion, Cardinal, 3.

Beza on new star, 68.

Bibliography of books and memoirs of T., 392.

Bille, Beate, mother of T., 11, 138, 284.

—— Eske, relation of T., 284, 308, 367.

—— Steen, uncle of T., 26, 91, 127, 201.

Blaev, pupil of T., 26, 91, 127; his son a printer, 374.

Bohemia, state of, 278.

Bongars, French historian, 137.

Books by T., 44, 162, 181, 182, 368, 369, 370.

Bording, chancellor of Mecklenburg, 246.

Brahe, family, 10.

—— Axel, brother of T., 283.

—— Cecily, daughter of T., 72, 367.

—— Christine, daughter of T., 72.

—— Claudius, son of T., 72.

—— Elizabeth, daughter of T., 72, 300, 301, 367.

—— Erik (Count Visingsborg), 310.

—— Jörgen, uncle of T., 12, 22.

—— Jörgen, son of T., 72, 294, 366.

—— Jörgen, nephew of T., 376.

—— Magdalene, daughter of T., 72, 73, 224, 283, 366, 367.

—— Otto, father of T., 11, 35.

—— Sophia, sister of T., 12, 71, 73, 201, 302, 306, 367.

—— Sophia, daughter of T., 72, 366.

—— Steen, brother of T., 35, 223, 245.

—— Tyge (Tycho), son of T., 72, 265, 283, 293, 366.

Brandeis Castle, 281.

Brandenburg, Elector of, intercedes for T., 255, 258.

Braun's map of Hveen, 90, 91, 94, 114.

Brucaeus, professor at Rostock, 131, 133, 163, 242.

Brunswick, Henry Julius, Duke of, visits T., 205; Otto of, wants horoscope, 285.

Buchanan, portrait of, 100, 203.

Bürgi, improves instruments, 120, 134, 212, 331; clocks, 324;trigonometrical formulas, 361.

Busch on new star, 64.

Calendar for 1573, 42, 52; for 1586, 125; for King, 156.

Camerarius, Joachim, at Leipzig, 17.

—— Elias, at Frankfurt-on-the-Oder, on new star, 60, 61, 63.

Canonry. *See* Roskilde.

Capuchins at Prague, 280.

Cardanus, 69, 166, 349.

Carellus, ephemerides, 18.

Carl Gustav, King of Sweden, 377.

Cassel observatory, 57, 79, 120, 134, 352.

Cassiopea, stars of, 39, 47, 328, 353. *See* New star.

Chanzler, inventor of transversals, 330.

Chemical studies of T., 36, 128.

Chiaramonte on distance of comets, 160, 371.

Chinese observations, 315, 343.

Christian IV. elected to the crown, 140; succeeds to it, 198; visits Hveen, 214; coronation, 230; T.'s letter to, 243; reply, 248; marriage, 256; T. sends books to, 267.

Christine, T.'s wife, 70, 366.

Chytræus, professor at Rostock, 24, 62, 242.

Clavius, subdivision of arcs, 223, 329; trigonometrical formulæ, 362.

Clepsydræ, 324.

Clocks, 324.

Colding, pupil of T., 302.

Cologne, Elector of, T. applies to, 269, 270.

Comets, different classes of, 45; nature of, 63, 160; parallax, 48, 131, 165, 208, 305; direction of tails, 6, 45, 166, 170; comet of 1577, 131, 158; book on, 162, 272; six other comets, 160, 161, 162.

Compass, T. repairs King's, 144.

Computing, 360.

Conjunctions of planets, 18, 52, 194, 195.

Copenhagen University, 13, 94, 110; T.'s house at, 200, 239.

Copernicus, life, 6; commentariolus, 83; instrument, 103, 125; observations, 123; solar system, 6, 172, 180, 208; T.'s opinion of this, 74: solar theory, 132, 333, 337; lunar theory, 338.

Corraducius, German Vice-Chancellor, 223, 266, 269, 271, 279, 298.

Correspondence, 131; with Landgrave and Rothmann, 134, 135, 208, 209, 228; with Magini, 212, 271.

Cosmopolitan character of astronomy, 115, 261.

Courland, Prince of, visits T., 217.

Craig, John, distance of comets, 208, 305, 369.

Crol, T.'s instrument-maker, 127, 211.

Cross-staff, 19, 357, 381.

Curtius, Albert, edits T.'s observations, 371, 372.

Curtius, J., German Vice-Chancellor, 223, 262, 329; his house at Prague inhabited by T., 278, 299, 365.

Customs at Elsinore, grant from, 109, 112.

Cyprianus. *See* Leovitius.

Dancey, French envoy, 42, 73, 85, 93, 131.

Danti, obliquity of ecliptic, 355.

Dee on new star, 63.

Diameter of sun, moon, planets, 191; of stars, 191; of moon, 344.

Diary, meteorological, at Hveen, 122.

Digges on new star, 58, 59; on transversal divisions, 330.

Dimensions of universe, 191.

Directions, astrological term, 148, 194.

Disciples. *See* Assistants.

Dresden, T.'s visit to, in 1598, 271.

Duel of T. and Parsbjerg, 26.

Eclipse of sun, 1560, 13; 1567, 27; 1598, 258, 259, 280, 341; lunar, 21, 26, 53, 55, 272; observations of eclipses used for lunar theory, 337; total eclipses denied by T., 344.

Ekdahl on ruins at Hveen, 378.

Elegy to Urania, 55; to Denmark, 254.

Elias Olsen, assistant to T., life, 122; expedition to Frauenburg, 123; calendar for 1586, 125.

Elixir of T., 130, 283.

Endowments of T., 108–113.

Ephemerides of Carellus, 18; Everhard, 269; Regiomontanus, 5; Stadius, 14, 17.

Eriksen, assistant to T., 301, 367.

Estate of T., 35, 223; promised in Bohemia, 279.

Fabricus, David, visits T., 260, 288.

Fabricius, Paul, on new star, 60, 61.

Farms, eleven, granted to T., 109, 235, 257.

Ferdinand I.'s villa inhabited by T., 298, 303.

Ferdinand II., Emperor, 291, 367, 370.

Fincke, mathematician, mission to Hveen, 240.

Fishponds at Hveen, 114, 257.

Flemlöse, assistant to T., 117; meteorology by, 119; sent to Cassel, 135.

Fool, T.'s, 128.

Forts, ancient, at Hveen, 91.

Fracastoro on direction of comets' tails, 6, 166; on obliquity of ecliptic, 355.

Frandsen, Hans, friend of T., 14, 44, 115.

Frangipani on new star, 64.

Frauenburg, expedition to, 123.

Frederick III., 264, 373, 374.

Frederick V., Elector Palatine, 365.

Friis, Chancellor, enemy of T., 230, 231, 236, 242.

Froben, printer, 253.

Funeral of T., 310.

Ganz, chronologist, 303.

Gellius Sascerides, pupil of T., 121; travels abroad, 181; intercourse with Magini, 212, 213; quarrel with Tycho, 224.

Gemma, Cornelius, on new star, 58, 60, 62, 63, 68; comet of 1577, 165, 171.

Gemma, Frisius, on cross-staff, 20; direction of comets' tails, 45, 166; instruments belonging to, 107; astronomical rings, 316.

Gemperlin, painter, 82, 101.

Geographical studies of T., 142, 358.

Germany, revival of learning in, 2.

Girsitz, in Bohemia, T.'s residence there, 283.

Globe, great, 32, 82, 99, 366; small, 46, 216.

Göggingen, near Augsburg, 30.

Gosselin on new star, 63.

Graminseus on new star, 68.

Grant of 6000 daler, 199.

Greek astronomy, 1.

Gregorian calendar, 132, 280.

Gustavus Adolphus, alleged prophesy on, 196.

Gyldenlöve, 376.

Gyldenstjern, cousin of T., 118, 284.

Hagecius on new star, 58, 64; meeting with T., 82; corresponds with T., 120, 131, 269, 270; parallax of comets, 131, 165, 171; receives T. at Prague, 279; death, 302.

Hainzel, J. B., 30.

Hainzel, Paul, 30; quadrant constructed for him by T., 31 observes new star, 60, 62; corresponds with T., 81, 131; observations of sun, 334.

Hannov sends T. the instrument of Copernicus, 125.

Hansen, assistant to T., observes comet of 1593, 162; eclipse of 1598, 259.

Hardeck, on former apparitions of new stars, 66.

Hasenburg, alchemist, 303.

Heiberg, on ruins at Hveen, 379.

Helsingborg Castle, 35.

Hemmingsen, theologian, 178, 203.

Henry III. of France, 69.

Heridsvad Abbey, 35, 73.

Hervart von Hohenburg, correspondent of Kepler, 292, 297, 340, 342.

Hind observes region around Nova, 67; orbits of comets, 162.

Hipparchus, star alleged to have been seen by him, 47, 49; observations of, 315; time-stars, 322; lunar inclination, 342; longitude of stars, 348, 354.

Hoffmann, Baron, friend of T. and Kepler, 292, 293, 296, 299.

Holk, H., 110, 111; Ditlev, 236.

Homilius, Professor, at Leipzig, 16, 17, 20, 330.

Horoscopes prepared by T., 20; of Prince Christian, 144; of two other princes, 154; wanted by Duke of Brunswick, 285.

Horrox, amount of annual equation, 341.

Huet, account of T.'s quarrel with Valkendorf, 233; visits Hveen, 377, 389.

Hulsius, bookseller, 370.

Hveen, island, offered to T.. 85; first visit to, 86; granted for life, 86; description of, 88; traditions about, 92; life at, 114; plan of granting it to T. for ever, 140; tenants at, 116, 236; clergyman at, 236; disturbances at, 240; T.'s opinion about, 256, 267, 375; kept by T. after departure, 284; subsequent fate, 275, 389.

Ibn Carfa, on giant instruments, 328.

Ibn Yunis used armillæ, 316; time determination by altitudes, 323; lunar inclination, 343; trigonometrical formulæ, 361.

Inclination of lunar orbit, 342.

Income of T., 257, 279. *See* Endowment.

Instruments of T., descriptions of, 19, 38, 101, 103, 107, 211; dismantled, 235; illustrated account of, 260; brought to Prague, 279, 283, 284; principle of, 317; subsequent fate, 365, 366, 368.

Interregnum, 198.

Iser Elver, 282.

James VI. visits T., 202.

Jeppe, T.'s fool, 128.

Jessenius of Wittenberg, 272, 295. 296, 311.

Joestelius, assistant to T., 288, 302, 362.

Johannes of Hamburg, assistant to T., 280.

Kaas, Chancellor, 115, 198, 199, 211, 222.

Karen, Andersdatter, 376.

Kepler, J., dates revival of astronomy from Tycho, 20; first correspondence with T., 259, 266; early life, 289; joins T., 293; quarrels with him, 295, 296; reconciled, 297; returns to Gratz, 297; settles at Prague, 299; new quarrel, 300; theory of Mars, 303, 304, 305; refutation of Reymers, 304; at T.'s death, 309, 386; later work, 312; annual equation, 341; on solar excentricity, 346; T.'s successor at Prague, 365; publishes T.'s book, 368; report on his unpublished works, 370; uses and retains T.'s MSS., 370; intends to publish them, 371.

Kepler, L., son of J. Kepler, possessed T.'s MSS., 374 ; sells them, 375.

Knieper, painter, 101.

Knudstrup, T.'s estate, 11, 35, 223, 378.

Krag, professor at Copenhagen, 225.

Kronborg Castle, 85, 101, 140, 143.

Kullagaard, 108.

Kullen lighthouse, 108, 109.

Lacaille, orbit of comet, 1593, 162.

La Hire, 375.

Lange, friend of T., 183, 201, 274, 275.

Latitudes, geographical, supposed to vary, 213, 263.

Lectures by T., 73.

Leipzig University, 16.

Leopold, Bishop of Passau, 367.

Leovitius, Cyprianus, 29, 63, 65.

Liddel, mathematician, 137, 184.

Lindauer, early observation of new star, 62.

Live, maid in T.'s house, 127.

Longitudes, absolute, 348; T.'s plan, 349; determined at Cassel, 352.

Longomontanus, assistant to T., his youth, 126; leaves T., 241; observes eclipse of 1598, 259; T.'s letter to him, 268, 283, 287; travels, 272; arrives at Prague, 288; works on lunar theory, 294, 305, 339; on Mars, 294, 303; returns to Denmark, 299; inscription on globe, 366.

Louis XIV., 374.

Lübeck, Bishop of, 266.

Lunar theory, 187, 294, 305, 338.

Luther, his horoscope, 69; his opinion of Copernican system, 177.

Maestlin, new star, 59; comet of 1577, 171, 181; Kepler's teacher, 289; consulted by Kepler, 297.

Magdeburg, T.'s instruments at, 278, 285.

Magini, T. sends him book on comet, 181; corresponds with T., 212, 262, 271; observes Mars, 214; book on instruments sent to him, 266; criticises T.'s lunar theory, 339; prostaphæresis, 362.

Magnitudes of stars, 354.

Maitland, Scotch chancellor, 203, 204.

Major, Johannes, 131, 132.

Manuscripts, T.'s, 370, 373, 374, 390.

Marcellinus, star mentioned by, 65.

Marius, Simon, 302.

Mars, distance of, 178; theory of, 213, 303, 346; oppositions observed, 214, 258, 303.

Mashallah, on astrolabes, 316.

Mathematical studies, 23, 40.

Maurice of Hesse, 212, 285.

Maurolycus on new star, 62.

"Mechanica," 260.

Mecklenburg, Duke of, 133, 158, 246, 270; T.'s money invested in, 247, 308.

Medal struck in 1595, 228.

Medicine, connection with astronomy, 24, 118; T.'s practice of, 129, 232, 260.

Melanchthon, on Copernican system, 177.

Meragha observatory, 320, 321.

Meridian observations, 321, 349; meridian line, 358, 388.

Meteorological rules, 119; diary at Hveen, 122.

Minkawitz, Imperial councillor, 309, 311.

Moestlin. *See* Maestlin.

Monavius, Jesuit, 120, 182, 268.

Money invested by T., 247, 308.

Moon, observations of, 337; tables of, 337. *See* Lunar theory.

Moryson, Fynes, traveller, 71, 89, 280.

Mühlstein, 286.

Müller, Johannes, assistant to T., 259, 268, 287, 288, 300.

Muffet, physician, 137.

Mule, assistant to T., 240, 283.

Munk, Admiral, 198, 215.

Munosius, on new star, 60, 61, 83.

Mysterium Cosmographicum, 289.

Nasir al-din Tusi, 320.

Naturalisation of T. in Bohemia, 307.

Neisse, great globe brought to, 366.

New stars alleged to have appeared in 945 and 1264, 65.

—— star, 1572; Tycho's first observations, 38; measures, 39; decline of light, 41; colour, 42; book by T. on, 44; nature of, 48, 63, 193; effect of, 49; other observations, 57; parallax, 60; when first seen, 61, 68, 193; whether it will appear again, 66; larger work on, 188.

—— star, rumour of one in 1578, 143.

Newton quotes Gemma's statement about new star, 62.

Nobility, Danish, 10.

Nodes, lunar, motion of, 343.

Nolthius on new star, 60.

Nonius, 320, 329.

Nordfjord estate, 110, 111, 231, 267.

Nose, T.'s, disfigured, 26, 71, 274.

Novara, teacher of Copernicus, 7; geographical latitudes, 213.

Nürnberg observatory, 4.

Nunez. *See* Nonius.

Obliquity of ecliptic, 123, 355.

Observations by T., earliest, 19, 27, 32, 35; of new star, 39, 41; in 1574 73,; at Hveen, 86, 94, 227; at Wandsbeck, 258; in Bohemia, 303.

Observatories, T.'s, 103, 200, 282, 286, 333.

Ohr, printer, 260.

Orange, Maurice of, 266, 269.

Oration on astrology, 74; funeral, 311.

Oxe, Peter, High Treasurer, 43; Inger, T.'s foster-mother, 43, 138, 247.

Papius, friend of Kepler, 292. Parallax of new star, 60; of comets, 131, 165; of planets, 189, 303; of sun, 335; of moon, 344.

Paris University, 15.

Parsbjerg, his duel with T., 26.

Pedersen, steward at Hveen, 259.

Pension of 500 daler, 85, 108, 234.

Peters on comet of 1585, 161; accuracy of T.'s observations, 357.

Peucer, professor at Wittenberg, 21, 23, 57, 58, 182, 370.

Picard, expedition to Hveen, 358, 374, 377.

Pinnules, improved, 331.

Planets, observations of, 227, 259, 345; theory by T., 180, 345.

Pliny, new star mentioned by, 42, 47.

Poetical effusions, 46, 55, 56, 115, 254.

Pontanus, assistant to T., 384.

Portraits belonging to T., 100, 106; of Danish kings, 143; of Tycho, 101, 228, 263.

Prætorius on new star, 61, 84.

Prague, description, 281; T. settles finally at, 298.

Pratensis, friend of T., 14, 42, 44, 46, 73, 85, 87.

Precession, 354.

Printing-press, 115, 163, 260, 272.

Progymnasmata, 186, 269, 272, 288, 307, 368.

Prostaphæresis, 361.

Prutenic tables, 8, 18, 19, 30, 52, 53, 133, 145, 155, 175.

Ptolemean system, 7, 172.

Ptolemy, works of, 14, 347; quadrant of, 320; lunar theory, 338; star catalogue of, 347.

Puehler's geometry, 331.

Pupils. *See* Assistants.

Purbach, 2; time determinations, 323; whether he used transversals, 330; trepidation, 355; trigonometry, 360.

Quadrant, great, at Augsburg, 31, 82; Tycho's, 101, 159, 320, 322.

Radius. *See* Cross-staff.

Raimundus of Verona on new star, 61, 64, 83.

Ramus, mathematician, 33.

Rantzov, friend of T., 116, 135, 253, 269, 270, 284.

Rasmus Pedersen, tenant of T., 217.

Ratisbon, coronation in 1575, 83.

Reduction of lunar motion to ecliptic, 344.

Refraction first noticed, 80, 336; neglected by Copernicus, 123; T.'s researches on, 334; cause of, 336; tables of, 265.

Regiomontanus, life, 3; ephemerides, 5; trigonometry, 47, 360; instruments, 317, 330; trepidation, 355.

Reinhold, 8, 18, 23, 124; his son, 83.

Reisacher on new star, 60, 64.

Reymers, Bar, on T.'s nose, 27; early life, 183; system of the world, 184; slanders T., 268, 273; flies from Prague, 288; corresponds with Kepler, 290; T. takes proceedings against him, he dies, 304; rumour of his having poisoned T., 312; prostaphæresis, 362.

Rhodius, assistant to T., 302.

Roemer brings T.'s MSS. to Paris, 374.

Roeslin on comet of 1577, 171; system of the world, 274.

Rogers, English envoy, 137, 182.

Rollenhagen, astrologer, 288, 312.

Rosenberg, friend of T., 303, 309.

Rosenkrands, Danish statesman, 198, 199, 215, 230; his son, Holger, 245, 301, 302.

Roskilde, prebend, 28, 109, 217, 221, 242; one granted to Flemlose, 118; treaty of Roskilde, 377. Rostock University, 24, 27; T.'s residence in 1597, 241.

Rothmann, 121, 134, 181, 183, 184; visits T., 206; abused by Reymers, 273; still alive in 1599, 288; absolute longitude, 352.

Rudolph II., 222, 261, 265, 277, 283, 285, 298, 306, 307.

Rudolphine tables, 301, 313, 365.

Rumph, Bohemian statesman, 279.

Sacrobosco, 3.

Safarik on region around Nova, 67.

Salary. *See* Income.

Salzburg, Archbishop of, 266.

Saturn, orbit of, 180.

Savelle, Thomas, T. sends letter to, 182.

Scaliger, Joseph, T. corresponds with, 255, 266, 270.

Schjellerup, orbit of comet 1580, 161.

Schönfeld, Victor, professor at Marburg, 127.

Schreckenfuchs, 82.

Schuler, Wolfgang, professor at Wittenberg, on new star, 58, 83.

Scripture and Copernican system, 177.

Scultetus, studies at Leipzig, 16; teaches T. about transversals, 20, 330; corresponds with T., 131, 133; on comet, 1577, 171; T. sends him a book, 182; T. consults him about printing, 288, 369.

Seccerwitz, poet, visits T., 136.

Seiffart, assistant to T., 302.

Sextant, 32, 38, 159, 325, 326.

Sights, improved, 331.

Sjöborg, Swedish antiquarian, 91, 378.

Snellius, 371.

Sörensen, king's physician, enemy of T., 232.

Soliman, Sultan, death foretold by T., 26.

Sophia, Queen, 138, 198, 200.

Stadius, ephemerides, 14, 17.

Stags, 210.

Star in Cassiopea. *See* New star.

Stars, fixed, observations of, 164, 351, 353; catalogue of, 227, 265, 347, 352, 353.

Stenwinchel, architect, 93, 101.

Stjerneborg, description, 103; ruins of, 378.

Stub, Professor, sent to Hveen, 240.

Sun, observations of, 94, 333; orbit of, 333, 346.

System of the world. *See* Copernicus, Ptolemy, Reymers, Tycho.

Tabit ben Korra on trepidation, 354, 355.

Tampach, publisher of T.'s books, 369, 370

Tenants at Hveen, 116, 235, 267; on the estate of the Roskilde prebend, 217.

Tengnagel, assistant to T, 242, 367; sent to Holland, 269; brings letter to Kepler, 293; Kepler's wife complains of him, 300; marries T.'s daughter, 301, 302; intends to prepare planetary tables, 365; gives it up, 312; subsequent career, 367; edits T.'s book on comet, 369; agreement with Kepler about MSS., 370.

Teynkirche at Prague, T. buried there, 310.

Thau, Valentin, mathematician, 16.

Theatrum astronomicum, proposed work by T., 182, 370.

Theon, first mention of trepidation, 354.

Thott, Otto, brother-in-law of T., 201; Tage, nephew, 201.

Time determinations, 159, 258, 322.

Timocharis used armillæ, 315.

Tomb of T., 311.

Torquetum, instrument not used by T, 317.

Traditions about Hveen, 92.

Transversal divisions, 20, 330.

Trautson, Emperor's chamberlain, 279.

Trepidation, 262, 354, 355.

Trigoni, astrological term, 49, 195.

Trigonometry, development of, 4, 360, 361.

Triquetrum, 58, 83, 84; not much used by T., 322.

Twilight, duration of, 206.

Tychonic system, 167, 180, 303

Ulfstand, Governor to Prince Christian, 215.

Ulrich, Prince, recovers great globe, 366.

Uraniborg, description, 93; life at, 114; ruins of, 377, 378.

Ursus. *See* Reymers.

Valeesius on new star, 60, 64.

Variation of the lunar motion discovered by T., 262, 338, 339.

Vedel, tutor to T., 15, 17, 20, 23; collects ancient ballads, 91, 92; corresponds with T., 131, 279, 283; visits T., 138, 201; dismissed from office of historiographer, 252.

Venice, T. visits, 81; intended expedition to Egypt from, 263.

Venus, comet's tail pointing to, 167, 170; used for determining absolute longitude, 349.

Vernier, 329.

Viète, 361.

Vignettes in T.'s books, 128.

Vitello, mentions refraction, 336.

Wallenstein, patron of Kepler, 371.

Walter, Michael, declaration about Reymers, 275.

Walther, Bernhard, 4; on refraction, 80, 336; instruments, 316, 330; time determination, 323; observatious of sun, 333; of planets, 345; of stars, 348.

Wandsbeck, 253.

Werner on trepidation, 355.

Wilhelm IV., Landgrave of Hesse, on new star, 57, 65, 68, 321; his youth, 79; T. visits him, 86; recommends T. to king, 84; alters his instruments, 120; correspondence with T., 134, 209, 228; intends to visit T., 136; on comet of 1577, 171; reads book on comet, 181; death, 212.

Willoughby d'Eresby, Lord, 137.

Winstrup, Bishop, 236, 377.

Wittenberg University, 22, 72, 271; T. visits, 29, 83, 271, 340.

Wittich, stay at Hveen, 119; never returns, 120; tells T. about Hagecius, 132; at Cassel, 120, 134, 331, 332; his books sold, 268; prostaphæresis, 361.

Woldstedt, orbit of comet, 1577, 357.

Wolf, Hieronimus, at Augsburg, 33, 81.

Workshop at Hveen, 108.

Würtemberg, Duke of, 370.

Young, Peter, 100, 203.

THE END.

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